Biomedical subjects

T Koga

Publications and source records attributed to T Koga.

At least 55 records · Page 3Linked to original sources

PubMed2001

Localization of human interleukin 13 receptor in non-haematopoietic cells.

Although the functional roles of interleukin (IL-)13 in haematopoietic cells are well investigated, those in non-haematopoietic cells remain to be addressed. IL-13 exerts its actions by binding to the IL-13 receptor (IL-13R) on target cells, which is composed of IL-13Ralpha1 and the IL-4 receptor alpha chain (IL-4Ralpha). However, there has been no study of localization of IL-13R in each tissue. To address this question, we generated monoclonal anti-IL-13Ralpha1 antibody, and performed immunohistochemistry using this antibody and anti-IL-4Ralpha antibody. Distribution of these two components was the same in all examined tissues. Staining was positive in keratinocytes, hair follicles, and sebaceous and sweat glands in skin; in ciliated respiratory epithelial cells in nasal tissue; in heart muscle cells; in foveola cells, gastric glands, and the smooth muscle layer in stomach; and in hepatocytes in liver. However, staining was undetectable in brain and bone marrow. Fibroblasts and endothelial cells were stained in some tissues. These results provide clues to elucidate the known pathological roles of IL-13 in atopic dermatitis and allergic rhinitis, as well as its unknown physiological roles.

Animals↗

PubMed2001

Chondrolysis of the glenohumeral joint following a color test using gentian violet.

Two patients developed chondrolysis following injection of 0.4% aqueous gentian violet into the glenohumeral joint to visualize a rotator cuff tear during surgery. In both cases, conventional radiographs revealed joint space narrowing 10-12 months after surgery. Histological examination of the humeral heads revealed loss of the articular cartilage.

Adult↗

PubMed2001

Recombinant proapoA-I(Lys107del) shows impaired lipid binding associated with reduced binding to plasma high density lipoprotein.

In the present study apoA-I (Lys 107del), a naturally occurring human apoA-I variant with a deletion of Lys 107, was expressed in E. coli to examine the effect of this mutation on lipid binding, cholesterol efflux and lecithin:cholesterol acyltranferase (LCAT) activation. Dimyristoyl phosphatidylcholine (DMPC) binding studies revealed slow interaction of proapoA-I(Lys107del) with DMPC relative to normal proapoA-I. After preincubation with human plasma lipoprotein (d<1.225 g/ml) for 1 h at 37 degrees C, 125I-labeled normal proapoA-I chromatographed as a single peak with the high density lipoprotein (HDL) fraction, whereas 125I-labeled proapoA-I(Lys107del) chromatographed with both HDL and free proapoA-I (26% of the radioactivity). Circular dichroism measurements showed that the alpha-helical content of lipid-bound proapoA-I (Lys107del) was reduced to 64 versus 73% of normal proapoA-I. Non-denaturing gradient gel electrophoresis of reconstituted HDL assembled with either proapoA-I(Lys107del) or normal proapoA-I showed that the mutation led to the formation of a second population of smaller rHDL particles. DMPC/proapoA-I(Lys107del) and normal DMPC/proapoA-I complexes exhibited a similar capacity to promote cholesterol efflux from fibroblasts. ProapoA-I (Lys107del) also activated LCAT similar to wild type proapoA-I and human plasma apoA-I. We conclude that deletion of Lys 107 substantially alters the lipid binding properties of the protein, which correlated with reduced binding to plasma HDL in vitro, but did not affect the capacity of the mutant/lipid complex to promote cholesterol efflux or activate LCAT.

Apolipoprotein A-I↗

PubMed2001

Psychological condition of patients complaining of halitosis.

OBJECTIVES: The purpose of this study was to examine the relationship between the actual degree of malodor and the psychological condition of patients complaining of halitosis. METHODS: The subjects consisted of 155 patients aged 46+/-17 years (mean+/-SD) who visited the Halitosis Clinic at Kyushu University Dental Hospital, Fukuoka, Japan. The Cornell Medical Index (CMI) Health Questionnaire was used to evaluate the psychological condition of patients. The degree of halitosis was estimated by the organoleptic test. RESULTS: Fifty-five percent of the patients had no or slight odor. Patients with a lower degree of halitosis showed a stronger psychopathological profile. There was a significant correlation between the degree of halitosis and the tendency toward neurosis (Spearman's rank correlation coefficient r=-0.37, P<0.001). CONCLUSIONS: The results suggest that psychological condition is closely associated with symptoms of patients complaining of halitosis. The CMI Health Questionnaire may be a helpful tool for the diagnosis of patients who complain of halitosis.

Chi-Square Distribution↗

PubMed2001

Effects of cetirizine and epinastine on the skin response to histamine iontophoresis.

Epinastine and cetirizine are second-generation, nonsedating and long-lasting antihistamines that are now frequently used for the allergic disorders. We have examined the inhibitory effects of these two drugs on the histamine-induced flare and wheal responses using iontophoresis at 1, 2, 4, 8 and 24 h after the oral administration by a double-blind, cross-over and placebo-controlled study. Both cetirizine and epinastine significantly inhibited the histamine-induced flare and wheal responses at 2 h after the oral administration when compared with placebo. The inhibitory effects of cetirizine and epinastine on the flare response lasted long until at 24 h, however, epinastine was less potent than cetirizine. The inhibitory effects on the wheal response was also clearly and significantly evident at 2-8 h by cetirizine and epinastine. At 24 h cetirizine only showed the significant inhibition on the histamine-induced wheal response. In contrast, epinastine seemed to exhibit the inhibitory capacity earlier than did cetirizine. The inhibitory action of the drugs on the histamine-induced wheal response peaked at 4 h after the oral administration. The histamine-induced itch sensation was also markedly or completely suppressed at 2-8 h by the drugs. Thus, both drugs exhibited the potent and long-lasting antihistamine activity on the skin responses induced by histamine iontophoresis.

Administration, Oral↗

PubMed2001

Induction of CD54 and CD58 expression in cultured human endothelial cells by beta-interferon with or without hyperthermia in vitro.

Human endothelial cells were treated by beta-interferon with or without hyperthermia at 42 degrees C for 90 min in vitro to investigate whether these modalities were able to increase the expression of either CD54 or CD58 on the surface of the endothelial cells. The results were that the population of the endothelial cells expressing both CD54 and CD58 increased 4 days after the treatment with beta-interferon, which was independent of hyperthermia. In contrast, the primarily isolated peripheral lymphocytes from a patient with malignant melanoma (disease free state) or normal individuals responded to neither beta-interferon nor hyperthermia in terms of the expression of CD54 or CD58. These results indicate that beta-interferon may activate endothelial cells to lead to the successive activation of the other immune cells in vivo.

Antineoplastic Agents↗

PubMed2001

Interleukin-8-positive neutrophils in psoriasis.

We performed an immunohistochemical study to try to determine the cellular source of interleukin-8 (IL-8) in psoriatic skin lesions. IL-8 was positively stained in the vast majority of neutrophils but not in the mononuclear cells, macrophages, or keratinocytes. IL-8-positive neutrophils were seen both in Munro's microabcesses in cases of psoriasis vulgaris and in a small spongiform pustule and much larger macropustules of Kogoj in cases of pustular psoriasis. Some IL-8-positive neutrophils were observed in the upper dermis of pustular psoriasis. The staining was considered to be specific because it could be completely blocked by preabsorption with recombinant IL-8. In addition, stimulation of human neutrophils with lipopolysaccharide (LPS) or tumor necrosis factor-alpha (TNF-alpha) for 18 h induced IL-8 production in vitro. In our study, IL-8 was expressed in the neutrophils of psoriasis, suggesting that neutrophils are one of the sources of IL-8 in psoriasis. The expression of IL-8 and the influx of neutrophils led us to speculate that the IL-8 autocrine and/or paracrine system functions in the formation of the microabcesses and pustules in proriasis.

Humans↗

PubMed2001

A new and simple Doppler method for measurement of fetal cardiac isovolumetric contraction time.

OBJECTIVES: The fetal cardiac isovolumetric contraction time is defined as the interval between mitral valve closure and aortic valve opening. The objective of this study was to develop a simple and reliable Doppler method for measuring fetal isovolumetric contraction time using a digital filtering and processing system. METHODS: Cardiac Doppler signals were recorded from 40 fetuses at 18-40 weeks' gestation using a continuous-wave ultrasound transducer. The raw signal was digitized, filtered and divided into five different frequency ranges: 250-375, 375-500, 500-750, 750-1000 and 1000-1500 Hz. To determine the most suitable filter setting for detecting mitral valve closure and aortic valve opening signals, we examined whether they were detected clearly in each filter range. RESULTS: Both mitral valve closure and aortic valve opening signals were detected clearly in the 500-1000 Hz range. The atrioventricular flow and outflow noises in the 250-500 and 1000-1500 Hz ranges helped us to identify the signals. It was found that dividing the raw signals into three ranges of 250-500, 500-1000 and 1000-1500 Hz was the most suitable digital-filter setting for measuring isovolumetric contraction time. CONCLUSIONS: We have developed a simple Doppler method for measuring fetal isovolumetric contraction time. The advent of digital processing has simplified the equipment and the simultaneous multidisplay of three different filtered signals enables easy and accurate measurement.

Aortic Valve↗

PubMed2001

Spontaneous regression of multiple seborrheic keratoses associated with nasal carcinoma.

Seborrheic keratoses are very common epidermal neoplasms. We describe a patient with seborrheic keratoses presenting multifocal spontaneous regression. The patient had a concurrent nasal adenoid cystic carcinoma. The simultaneous regression of seborrheic keratoses ceased after total resection of the nasal carcinoma. Histological examination revealed marked infiltration of mononuclear cells, including CD4+, CD8+, CD68+ and cutaneous lymphocyte-associated antigen-positive cells, with profound accumulation of CD1a+ dendritic cells. Although apoptotic keratinocytes were not found in the lesional epidermis by histology, the majority of keratinocytes in the regressing seborrheic keratosis were positively stained by the TUNEL method. We postulate that the internal malignancy may induce spontaneous regression of seborrheic keratoses.

Aged↗

PubMed2001

Characteristics of patients complaining of halitosis and the usefulness of gas chromatography for diagnosing halitosis.

OBJECTIVE: The purpose of this study was to examine the characteristics of patients complaining of halitosis and to evaluate the diagnostic accuracy of 3 methods of measuring halitosis. STUDY DESIGN: The actual degree of halitosis was determined through use of an organoleptic test in 155 patients aged 46 +/- 17 years (mean +/- SD). The volatile sulfur compounds (VSCs) were determined with gas chromatography and with sulfide monitoring. RESULTS: The organoleptic test revealed that 55% of the subjects had either no mouth odor or slight mouth odor. There was a significant correlation between the organoleptic score and the total VSC level as determined through use of other methods. The critical discrimination value of the total VSC level was calculated to be 0.057 ppm for gas chromatography and 0.117 ppm for sulfide monitoring; high sensitivity and specificity were obtained when the gas chromatography value was used. The amount of tongue coating was significantly greater in the halitosis-positive group than in the halitosis-negative group, whereas there was no difference in salivary flow rate between the 2 groups. CONCLUSION: These results indicate that determining VSCs with gas chromatography is a useful means of diagnosing halitosis.

Chi-Square Distribution↗

PubMed2001

A revisit of mucosal IgA immunity and oral tolerance.

Induction of mucosal immunity by oral immunization with protein antigen alone is difficult: potent mucosal adjuvants, vectors, or other special delivery systems are required. Cholera toxin (CT) has been shown to be an effective adjuvant for the development of mucosal vaccines and, when given with vaccine, induces both mucosal and systemic immune responses via a Th2 cell-dependent pathway. However, and in addition to potential type-I hypersensitivity, a major concern for use of mucosal adjuvants such as CT is that this molecule is not suitable for use in humans because of its inherent toxicity. When we examined the potential toxicity of CT for the central nervous system, both CT and CT-B accumulated in the olfactory nerves/epithelium and olfactory bulbs of mice when given by the nasal route. The development of effective mucosal vaccines for the elderly is also an important issue; however, only limited information is available. When mucosal adjuvanticity of CT was evaluated in aged mice, an early immune dysregulation was evident in the mucosal immune system. The present review discusses these potential problems for effective mucosal vaccine development. Tolerance represents the most common and important response of the host to environmental antigens, including food and commensal bacterial components, for the maintenance of an appropriate immunological homeostasis. We have examined whether Peyer patches could play a more important role for the maintenance of oral tolerance. Using Peyer patch-null mice, we found that mice lacking this gut-associated lymphoid tissue retained their capability to produce secretory IgA antibodies but did not develop normal oral tolerance to protein antigens.

Administration, Inhalation↗

PubMed2001

Interferon-gamma production in peripheral lymphocytes of patients with tinea pedis: comparison of patients with and without tinea unguium.

The precise mechanism of the host defense that protects the nail from dermatophyte invasion is not known. Recent immunological findings in dermatophytosis suggest the hypothesis that the T helper 1 (Th1) response may play a role in protecting the nail from dermatophyte invasion. Our present study focused on interferon-gamma (IFN-gamma) release in patients with tinea pedis with or without tinea unguium, and pathogenesis of tinea unguium is discussed in relation to the association with a possible deficiency of Th1 response in the host defense mechanism. The production of IFN-gamma by peripheral blood mononuclear cells from the patients with tinea unguium in response to stimulation with trichophytin was not impaired in contrast to that from the patients without tinea unguium. Comparable lymphocyte proliferation to trichophytin was observed in both groups. Normal healthy persons with no clinical evidence of tinea could be divided into two groups based on lymphocyte proliferation and IFN-gamma production in response to trichophytin: high responder and low responder, with high responders being correlated with a clinical history of previous tinea pedis. In this study, a lack of a Th1 response to dermatophyte antigen was not shown in patients with tinea unguium by measuring the release of IFN-gamma, which plays a role in the effector phase of the delayed-type hypersensitivity reaction. A deficiency in the Th1 response to dermatophyte antigen, therefore, does not appear to play an important role in the establishment of tinea unguium.

Female↗

PubMed2001

Effect of plasma metabolites of (+)-catechin and quercetin on monocyte adhesion to human aortic endothelial cells.

BACKGROUND: Flavonoids may exert their health benefit in cardiovascular disease by modulating monocyte adhesion in the inflammatory process of atherosclerosis. Most in vitro studies used forms of flavonoids present in food rather than forms that appear in plasma after ingestion. OBJECTIVES: We tested the effects of plasma metabolites of (+)-catechin and quercetin on the modulation of monocyte adhesion to human aortic endothelial cells (HAEC) and on the production of reactive oxygen species (ROS). DESIGN: Plasma extracts of flavonoid metabolites were prepared after intragastric administration of pure compounds to rats. The plasma preparations contained sulfate or glucuronide conjugates or both and methylated forms. We measured adhesion of U937 monocytic cells to HAEC and the production of ROS in HAEC when cells were pretreated with either pure compounds or plasma extracts from control or treated rats. Adhesion assays were performed with HAEC stimulated with interleukin (IL)-1 beta or U937 cells activated with phorbol myristyl acetate; ROS were measured after challenging HAEC with IL-1 beta or hydrogen peroxide. RESULTS: Pretreatment of HAEC with (+)-catechin metabolites inhibited U937 cell adhesion to IL-1 beta-stimulated cells, whereas pretreatment with intact (+)-catechin had no effect. Generation of ROS in hydrogen peroxide-stimulated HAEC was inhibited by (+)-catechin, its metabolites, and control plasma extract, whereas ROS generation in IL-1 beta-stimulated HAEC was inhibited by (+)-catechin metabolites only. In contrast, quercetin inhibited U937 cell adhesion to IL-1 beta-stimulated HAEC, whereas its metabolites were not effective. CONCLUSIONS: Metabolic conversion of flavonoids such as (+)-catechin and quercetin modifies the flavonoids' biological activity. Metabolites of flavonoids, rather than their intact forms, may contribute to the reported effects of flavonoids on reducing the risk of cardiovascular disease.

Animals↗

PubMed2001

The fetal cardiac isovolumetric contraction time in normal pregnancy and in pregnancy with placental vascular disease: the first clinical report using a new ultrasound technique.

OBJECTIVE: To study the fetal cardiac isovolumetric contraction time in normal and complicated pregnancies with placental vascular disease using a newly developed digital Doppler cardiography system. DESIGN: A preliminary case-control study. SETTING: Tertiary referral hospital. SAMPLE: One hundred and sixteen normal fetuses (20 to 40 weeks) and 55 complicated pregnancies with placental vascular disease as documented by a high systolic: diastolic ratio in the umbilical artery Doppler flow study. METHOD: A digital Doppler cardiography system with a high sampling rate (4,000 Hz) was used to detect the fetal cardiac valvular movements. The isovolumetric contraction time was measured as the interval between the mitral valve closing and the aortic valve opening with a built-in scale device. RESULTS: In normal pregnancy the isovolumetric contraction time remained remarkably constant with gestation and fetal heart rate. Comparison between clinical outcome and the isovolumetric contraction time of the complicated fetuses who were born within a week after the last determination of the isovolumetric contraction time revealed a strong correlation between prolonged isovolumetric contraction time duration and abnormalities in the perinatal course (non-reactive fetal heart rate pattern, low pulsatility index in the fetal middle cerebral artery Doppler flow and low birthweight infant). CONCLUSIONS: The isovolumetric contraction time is constant with gestation and fetal heart rate in normal pregnancy. In the presence of placental vascular disease a prolonged fetal isovolumetric contraction time predicts adverse outcome.

Case-Control Studies↗

PubMed2001

Prognostic significance of natural killer cell activity in patients with gastric carcinoma: a multivariate analysis.

OBJECTIVE: Natural cytotoxicity, mediated by natural killer (NK) cells, has been believed to play an important role in inhibiting experimental tumor metastasis, and diminished NK cell activities leads to a high incidence of tumor occurrence. Despite convincing evidence from experimental studies, the role of NK cells in the immunological surveillance against cancer in human is poorly defined. METHODS: The present study was based on a retrospective analysis of data on 156 patients with gastric cancer, who were surgically treated in the Department of Surgery II, Kyushu University Hospital from 1993 to 1996. All patients were examined for NK cell activity based on a peripheral blood sampling done preoperatively. RESULTS: Significant association between NK cell activity and clinicopathological parameters including tumor size, lymphatic involvement, vascular involvement, and lymph node metastases was evident. When comparing the two groups according to NK cell activity, tumors with low NK cell activity tend to have lymphatic involvement. The 5-yr survival rates were 94.6% and 72.3% for those with NK cell activity > 25% lysis and < or = 25% lysis, respectively, the value being statistically significant (p < 0.05). The independent risk factors for prognosis examined by logistic regression analysis were lymphatic involvement. NK cell activity, depth of tumor invasion, and lymph node dissection. CONCLUSIONS: These current data showed that NK cell activity may be related to tumor volume and dissemination. Measurement of preoperative NK cell activity may be pertinent for the prognosis of patients with gastric cancer and for follow-up clinical management.

Cytotoxicity, Immunologic↗

PubMed2001

Passive immunization with milk produced from an immunized cow prevents oral recolonization by Streptococcus mutans.

Cell surface protein antigen (PAc) and water-insoluble glucan-synthesizing enzyme (GTF-I) produced by cariogenic Streptococcus mutans are two major factors implicated in the colonization of the human oral cavity by this bacterium. We examined the effect of bovine milk, produced after immunization with a fusion protein of functional domains of these proteins, on the recolonization of S. mutans. To prepare immune milk, a pregnant Holstein cow was immunized with the fusion protein PAcA-GB, a fusion of the saliva-binding alanine-rich region (PAcA) of PAc and the glucan-binding (GB) domain of GTF-I. After eight adult subjects received cetylpyridinium chloride (CPC) treatment, one subgroup (n = 4) rinsed their mouths with immune milk and a control group (n = 4) rinsed with nonimmune milk. S. mutans levels in saliva and dental plaque decreased after CPC treatment in both groups. Mouth rinsing with immune milk significantly inhibited recolonization of S. mutans in saliva and plaque. On the other hand, the numbers of S. mutans cells in saliva and plaque in the control group increased immediately after the CPC treatment and surpassed the baseline level 42 and 28 days, respectively, after the CPC treatment. The ratios of S. mutans to total streptococci in saliva and plaque in the group that received immune milk were lower than those in the control group. These results suggest that milk produced from immunized cow may be useful for controlling S. mutans in the human oral cavity.

Adult↗

PubMed2001

Identification of Actinobacillus actinomycetemcomitans serotypes by multiplex PCR.

Oligonucleotide primers specific for gene clusters involved in the biosynthesis of serotype-specific polysaccharide antigens were designed to identify Actinobacillus actinomycetemcomitans serotypes a to e using the multiplex PCR. This method may be useful for serotype-specific genotyping rapidly and directly from clinical samples containing various organisms.

Actinobacillus Infections↗

PubMed2001

Nanofabrication of helical peptide-shelled dendrimers.

This study describes nanofabrication of helical peptide-shelled dendrimers using a Langmuir monolayer technique. Poly(amido amine) dendrimers (G3) modified with poly(gamma-benzyl-L-glutamate) [number averaged degree of polymerization, n = 12, 17, and 34 (G3-PBLGs hereafter)] were newly prepared by graft polymerization of gamma-benzyl-L-glutamate-N-carboxy anhydride initiated with amino groups of the dendrimer surface. The hydrodynamic diameters of G3-PBLGs were determined to be 6.9 +/- 0.7, 8.2 +/- 1.0, and 11.9 +/- 1.7 nm for n = 12, 17, and 34, respectively, by means of dynamic light scattering. These values were consistent with the theoretical diameters of G3-PBLGs, which were calculated by considering the alpha-helical PBLG segment length. G3-PBLGs were found to form stable monomolecular films with high collapse pressures above 40 mN m-1 at the air-water interface. In addition, these monolayers could be successfully transferred onto various solid substrates. Circular dichroism and Fourier transfer infrared spectroscopies of the deposited G3-PBLGs monolayers showed that PBLG segments took an alpha-helical conformation over a wide range of surface pressure even on solid substrates as well as in bulk solutions. Monolayer thicknesses of these Langmuir-Blodgett films, estimated by x-ray photoelectron spectroscopy and atomic force microscopy, were compatible with the hydrodynamic diameters of G3-PBLGs.

Biomimetic Materials↗